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  • Life and Medical Sciences  (2)
  • Neobellieria bullata (Insecta)  (2)
  • 1
    ISSN: 1432-0878
    Keywords: Allatostatin ; Juvenile hormone ; Insect brain ; Neuropeptide ; Corpus allatum ; Corpus cardiacum ; Neurosecretory cells ; Schistocerca gregaria ; Locusta migratoria ; Neobellieria bullata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Methanolic brain extracts of Locusta migratoria inhibit in vitro juvenile hormone biosynthesis in both the locust L. migratoria and the cockroach Diploptera punctata. A polyclonal antibody against allatostatin-5 (AST-5) (dipstatin-2) of this cockroach was used to immunolocalize allatostatin-5-like peptides in the central nervous system of the locusts Schistocerca gregaria and L. migratoria and of the fleshfly Neobellieria bullata. In both locust species, immunoreactivity was found in many cells and axons of the brain-retrocerebral complex, the thoracic and the abdominal ganglia. Strongly immunoreactive cells were stained in the pars lateralis of the brain with axons (NCC II and NCA I) extending to and arborizing in the corpus cardiacum and the corpora allata. Although many neurosecretory cells of the pars intercerebralis project into the corpus cardiacum, only 12 of them were immunoreactive and the nervi corporis cardiaci I (NCC I) and fibers in the nervi corporis allati II (NCA II) connecting the corpora allata to the suboesophageal ganglion remained unstained. S. gregaria and L. migratoria seem to have an allatostatin-like neuropeptide present in axons of the NCC II and the NCA I leading to the corpus cardiacum and the corpora allata. All these data suggest that in locusts allatostatin-like neuropeptides might be involved in controlling the production of juvenile hormone by the corpora allata and, perhaps, some aspects of the functioning of the corpus cardiacum as well. However, when tested in a L. migratoria in-vitro juvenile hormone-biosynthesis assay, allatostatin-5 did not yield an inhibitory or stimulatory effect. There is abundant AST-5 immunoreactivity in cell bodies of the fleshfly N. bullata, but none in the CA-CC complexes. Apparently, factors that are immunologically related to AST-5 do occur in locusts and fleshflies but, the active protion of the peptide required to inhibit JH biosynthesis in locusts is probably different from that of AST-5.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0878
    Keywords: Key words: Allatostatin ; Juvenile hormone ; Insect brain ; Neuropeptide ; Corpus allatum ; Corpus cardiacum ; Neurosecretory cells ; Schistocerca gregaria ; Locusta migratoria ; Neobellieria bullata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Methanolic brain extracts of Locusta migratoria inhibit in vitro juvenile hormone biosynthesis in both the locust L. migratoria and the cockroach Diplo-ptera punctata. A polyclonal antibody against allatostatin-5 (AST-5) (dipstatin-2) of this cockroach was used to immunolocalize allatostatin-5-like peptides in the central nervous system of the locusts Schistocerca gregaria and L. migratoria and of the fleshfly Neobellieria bullata. In both locust species, immunoreactivity was found in many cells and axons of the brain-retrocerebral complex, the thoracic and the abdominal ganglia. Strongly immunoreactive cells were stained in the pars lateralis of the brain with axons (NCC II and NCA I) extending to and arborizing in the corpus cardiacum and the corpora allata. Although many neurosecretory cells of the pars intercerebralis project into the corpus cardiacum, only 12 of them were immunoreactive and the nervi corporis cardiaci I (NCC I) and fibers in the nervi corporis allati II (NCA II) connecting the corpora allata to the suboesophageal ganglion remained unstained. S. gregaria and L. migratoria seem to have an allatostatin-like neuropeptide present in axons of the NCC II and the NCA I leading to the corpus cardiacum and the corpora allata. All these data suggest that in locusts allatostatin-like neuropeptides might be involved in controlling the production of juvenile hormone by the corpora allata and, perhaps, some aspects of the functioning of the corpus cardiacum as well. However, when tested in a L. migratoria in-vitro juvenile hormone-biosynthesis assay, allatostatin-5 did not yield an inhibitory or stimulatory effect. There is abundant AST-5 immunoreactivity in cell bodies of the fleshfly N. bullata, but none in the CA-CC complexes. Apparently, factors that are immunologically related to AST-5 do occur in locusts and fleshflies but, the active portion of the peptide required to inhibit JH biosynthesis in locusts is probably different from that of AST-5.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 72 (1968), S. 39-42 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cytological effects of 2 mM hydroxyurea upon Chinese hamster cells at various phases of the cell cycle were examined. Cells in the G1, G2, or M phases of the generation cycle treated with hydroxyurea showed no chromosomal aberrations. Cell treated in S phase became moribund and eventually lysed. Some of these moribund S cells reached mitosis much later and were found to have chromatid aberrations. Cells in the log phase of growth, surviving exposure to 2 mM hydroxyurea for six hours, also showed no aberrations. Thus, viable (colony-forming) cells, resulting from synchrony procedures with hydroxyurea are free of chromosomal aberrations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0192-253X
    Keywords: Transport ; nicotinic acetylcholine receptor ; sympathetic neurons ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Several recent studies have used antisense oligonucleotides in the nervous system to probe the functional role of particular gene products. Since antisense oligonucleotide-mediated block of gene expression typically involves uptake of the oligonucleotides, we have characterized the mechanism of this uptake into developing neurons from embryonic chickens. Antisense oligonucleotides (15 mers) added to the bathing media are taken up into the embryonic chicken sympathetic neurons maintained in vitro. A portion of the oligonucleotide uptake is temperature dependent and saturates at extracellular oligonucleotide concentrations ≥ 20 μM. This temperature sensitive, saturable component is effectively competed by single nucleotides of ATP and AMP and is reminiscent of receptor-mediated endocytosis of oligonucleotides described in non-neuronal cells. The efficiency of the oligonucleotide uptake system is dependent on the developmental stage of the animal but independent of the number of days that the neurons are maintained in vitro.Following the uptake of antisense oligonucleotides directed against ion channel subunit genes expressed by these neurons (nicotinic acetylcholine receptor subunit α3; nAChR α3), biophysical assays reveal that the functional expression of the target gene is largely blocked. Thus the number of wild type nAChR channels expressed is decreased by =80%-90%. Furthermore, following antisense deletion of α3, “mutant” nAChRs with distinct functional characteristics are expressed.In sum, these studies characterize the uptake of antisense oligonucleotide and demonstrate the functional block of specific gene expression in primary developing neurons. In addition, the functional studies emphasize the need for sensitive and specific assay following antisense deletion, since other homologous gene products may substitute for the targeted gene resulting in new phenotypes that are subtly different from wild type. © 1993Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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